Esophageal tumors in sheep: some ecological observations.
D000818:Animals; D003300:Copper; D004463:Ecology; D004777:Environment; D004781:Environmental Exposure; D004938:Esophageal Neoplasms / Q000139:chemically induced / Q000209:etiology* / Q000662:veterinary; D009538:Nicotine; D012756:Sheep; D012757:Sheep Diseases / Q000209:etiology*; D013019:South Africa; D013431:Sulfates
D013431:Sulfates; D009538:Nicotine; D003300:Copper